Testing makes perfect, finds memory retrieval research

Conventional wisdom holds that if you want to learn something, study, study, study. But new psychological research suggests the mantra should be "test, test, test."

In Science (Vol. 319, No. 5,865), a team of psychologists reports that students who were repeatedly tested on material significantly outperformed those who repeatedly studied it. Jeff Karpicke, PhD, of Purdue University in West Lafayette, Ind., and Henry L. "Roddy" Roediger, PhD, of Washington University in St. Louis, studied a variety of learning procedures with students memorizing a list of 40 Swahili-English word pairs (e.g., mbwa means dog). Initially, all students studied a list of the 40 words and then tested on them.

Next, they divided students into four groups. One group studied and was tested on all the words every time. A second group was tested on all the words, but words they got correct were dropped from their study sheets. A third group studied all the words every time but had correct answers dropped from their tests. Finally, a fourth group had correct answers dropped from both their study sheets and tests. After four study and test periods, all students in all groups scored around 100 percent.

A week later, Karpicke and Roediger tested students one final time on the word pairs. They found that the two groups that were repeatedly tested on the full set of words got about 80 percent of the word pairs correct in the final test, while the other groups--who studied all the words but weren't repeatedly tested on their correct answers--only knew about 35 percent.

Testing may work better than straight-up studying because remembering is a skill that takes practice, Karpicke explains.

"When people are practicing memory retrieval while they're learning, they're practicing the same skill they'll need to recall the information on a later test."